PHOTODYNAMIC THERAPY FOR HERPES-SIMPLEX - CRITICAL-REVIEW

The purpose of this review is to summarize available experimental and clinical data concerning benefits and potential risks of photodynamic therapy for oral and genital herpes simplex virus infections. Since such infections are a source of discomfort and pain, and since recent evidence links the virus itself with carcinogenesis, clinicians have felt an increased need for more effective therapy for herpesvirus infections. In 1973 a human clinical therapeutic procedure based on photodynamic inactivation was developed. The treatment consists of applying a photosensitizing dye to herpesvirus lesions and then exposing them to visible light. A number of human clinical trials have been completed; some of these show reduction of herpesvirus infectivity, whereas others question the efficacy of the procedure. Data from a number of in vitro virus-host cell studies suggest the procedure may be potentially carcinogenic and therefore clinically hazardous. Thus a controversy exists concerning further use of the treatment. This review gives the reader a basis for understanding the controversy and included basic principles of photodynamic inactivation, medical aspects of herpesvirus infections, development of the therapeutic procedure, results of clinical studies, and results of in vitro studies which indicate potential long-term side effects. © 1979.